Locomotive stoker



Dec. l0, 1940. c, T. HANSEN LOCOMOTIVE STOKER Filed May 19, 19258 n.` s me. m. mlm m ma m lH A Aals Patented Dec. l0, 1940 UNITED STATES PATENT OFFICE ard Stoker Company, Incorporated, a corporation of Delaware Application May 19, 193s, serial No. 208,741

4 Claims.

This invention relates to stokers and particularly to locomotive stokers employing a screw conveyor for urging fuel upwardly to a point of distribution.

In stokers of this type, the conveyor screw which is disposed in the lower portion of a fuel feeding conduit is provided on its terminal end with a double screw flight so that the fuel may receive two upward impulses during each revolution of the screw. This produces a more continuous delivery of fuel to the distributor with the result that a more steady and uniform supply of fuel is distributed over the firebed.

While it is recognized that a still more continuous delivery of fuel would be attained by providing additional flights, it is not usually possible to provide the terminal end of the screw with more than a double flight because the addition of more than one extra screw flight between the normal screw nights would reduce the space necessary for the emcient conveyance of fuel.

It is the principal object of this invention to provide, in a stoker of the type described, a conveyor screw having its flights arranged to impart to the fuel more than two upward impulses during a single revolution of said screw and without materially reducing the fuel carrying capacity of said screw.

A further object of this invention is to provide a conveyor screw having a portion provided with a double flight of normal winding and a portion having a flight of reverse winding.

It is also an object of this invention to so arrange the flights of the normal and reverse windings that .impulses are imparted to the fuel at regularly spacedl intervals during one complete revolution of the screw..

Specifically, it is the object of this invention to improve, in the manner herein specined, a Stoker in which the conveyor screw is driven from its forward end. v

Other objects reside in the novel form of the screw per se and in its specific relation with otherparts, substantially as described in the following specification which is accompanied by the drawing, in which Fig. l is a vertical section taken longitudinally along the medialplane of the locomotive with the invention in similar section;

Fig. 2 is a perspective of the conveyor screw forming an essential part of this section; and

Fig. 3 is a transverse cross section through a conveyor screw showing its functions diagrammatically.

` On this drawing, L is a locomotive having a` boiler I0 supported upon a frame II. The boiler I0 is provided witha rebox I2, the backwall I3 of which has a-ring opening I4 above the grates I5.4 Rearward of the backwall I3 is a cab deck I6 upon which is supported an apron I1 for bridging the space between the cab deck I6 and the deck I8 of the tender T, the latter including an underframe I9.

A stoker S conveys fuel from the tender T to the flrebox I2 of the locomotive L. It includes a conveyor conduit 20 leading forwardly from the tender and housing a screw 2| therein. VThe forward end of the conduit 20 is connected by a ball joint 22 to the rearward end of an elbow conduit 23, the latter forming a portion of a fuel elevator E disposed on the locomotive L. The elbow 23 includes a, horizontally directed lower portion 24 and an angularly inclined upward portion 25 provided at its upper end with a rabbeted cr counter-bored seat 26 for receiving a tubular conduit 21. shallow casing 28' provided with a reanwali 29, and side walls such as 3.0 which extend forwardly into the lower portion of the firing opening I4. A lid 3| covers the upper side of the casing` 28. Thai; portion of the firing opening I4 above the casing 28 is closed by a redoor 82. v

Fuel is urged upwardly through the elbow 23 and the Vconduit 21 by a screw C of novel formation which is disposed within the horizontal portion 24 of the elbow 28. 'Ihe rearwall` 29 of the casing 28 carries a pressure uid distributor head 33 receiving fluid under pressure from a pipe 84. As the fuel enters the casing 28, `the distributor head projects the fuel forwardly across a plate 35 which extends into the ilrebox I2 through the lower portion of the opening I4. A pin `36 secures the plate 35 to the conduit 21 against fore and aft movement while a lug 31, which is formed at each side of the plate 35, rests on a sidewall 38 of the casing 28 for preventing downward movement of said plate 35. If desired, auxiliary jets such as 38 may be provided at the forward end of the plate 35 for directing fuel laterally into the rebox I2.

The screw C is driven from its forward end by a gear 38 which is housed within a casing 40 formed with the elbow conduit 23. A shaft 4I is suitably journaled in the casing 40 and carries the gear 39 whereby said shaft 4I is rotated at a suitable rate of speed. Internally, the shaft 4I is provided with a polygonal socket 42 for telescopically receiving the polygonal portion 43 of the hub 44 upon which are wound the llightsof conveyor screw C. The hub 44 at its rearward i end is forked to provide a jaw45, forming one element of a universal joint 48 between the screw C and the screw 2 I. Since the conduit 2li is tele- Immediately above the conduit 21 is a wardly. its function is considerably dinerent from that of a screw which merely conveys fuel axially. The function of a horizontally disposed conveyor in elevating material is shown diagrammatically in Fig. 3, wherein f represents the spirally wound night ofl a conveyor ,screw C, the night f being in transverse section.

Assuming the screw C to be revolving in the direction shown by the arrow, it will be observed that the night f elevates fuel during traverse of the straight angle a (180) in traversing straight angle a' (180) the night f will not lift material. In traversing angle a, the night f elevates material most enlciently while passing through angle b, which is approximately 90 in extent. This is apparent from an inspection of Fig. 3 from which it will be observed that in traversing the primary angle d (45) and the nnal angle c (45), the night f rges the material a greater distance horizontally than vertically. In traversing angle b (180), the night f moves the material moreV 4nearly vertically than horizontally.

Thus it will be apparent that a. horizontally positioned conveyor screw having but a single night wound around its hub or stem will elevate material most enlciently through substantially one-fourth (1A) of its turn. In order to provide a screw which will elevate material einciently throughout a complete turn thereof, it would be necessary to provide three additional screw nights between the normal night. To do so would materially reduce the carrying capacity of the screw because the three extra screw nights would occupy space necessary for the material being conveyed and elevated.

According to this invention, the screw conveyor C is so arrangedthat it will elevatefuel most efficiently without materially reducing the carrying capacity of the screw and without obstructing the free now of fuel. Betweenthejaw 45 and the polygonal portion 43, the hub M of the screw C has wound thereon a'night l0 which is arranged to convey fuel forwardly thence upwardly when the screw C is rotated in the direction in dicated by the arrow in Fig. 2. Another night 5l is also wound about the hub 4I and it is substantially co-extensive in length with the night M but arranged so that its forward end is spaced 180 from the night 50.

Since the screw C is driven from its forward end, the polygonal portion 43 of the screw 'hub I4 may sometimes form an obstruction to the free passage of fuel upwardly. To obviate this, that portion of the screw hub M immediately rearward of the polygonal portion 43 is provided with a pair of nights 52, 53 wound in a direction such that fuel will be urged rearwardly and upwardly when the screw C is rotated in the direction indicated. Preferably, these "reverse" nights 52, 53 are spaced 180 from each other andso related with theV forward nights 50, 5I so as to be approximately away therefrom. In this manner, there is provided a conveyor screw having a double night portion for conveying fuel forwardly and upwardly and a double night portion for conveying fuel rearwardly and upwardly, the two double night portions being so related with each other that the most efficient lifting action is imparted to the fuel during the entire revolution of the screw. The nights 52, 53 not only serve to prevent fuel from lodging underneath the polygonal shaft portion 43, but also aid in the continuous upward elevation of the fuel.

In operation, the conveyor screw 2i conveys fuel `forwardly into the elbow conduit 23 wherein the screw C picks up the fuel and advances it for- 5 wardly and upwardly. As shown in Figs. 1 and 2, the reverse night 52 is midway through the angle b (Fig. 3), and the forward night 6I is approaching this angle b for imparting continuous upward movement to the fuel. Thereafter, the reverse night 53 will enter the angle b, to be followed in turn by the forwardf night 50. The fuel is thus elevated through the elbow conduit 23 and the upstanding conduit 21 by a screw which imparts a vertical movement to the fuel throughout a complete revolution of the screw. This will result in more even and continuous delivery of fuel to the distributing means without obstructing the free passage oi the fuel in the elbow conduit 23. Due to the fact that the elbow Vconduit 23 is completely nlled with fuel to a point adjacent the jaw 45, the "reverse nights 52, 53 will not push the fuel an appreciable distance rearwardly but will merely lift the fuel. The forward and reverse double night portions act somewhat opposite to each other with reference to forward and rearward conveyance of fuel, but the resultant force is in an upward direction.

From the foregoing, it will be apparent that the stated objects of this linvention have been achieved by the structure which is now to be claimed.

Iclaim: l

1. A conveying system comprising an upwardly 35 extending conduit and a conveyor screw at the base of said conduit for urging material upwardly in said conduit, said conveyor` screw having 'a double helical night portion wound to urge material normally in one direction and a double helical night portion spacedaxially from said nrst named double helical night portion and wound to urge material in the opposite direction, the adjacent terminal edges of said night portions being spaced 90 degrees apart.

2. As a new article of manufacture, a conveyor screw having a double helical night portion woundy to urge material in onedirection and a double helical night portion spaced axially from said first named double helical night portion and wound to urge material in the opposite direction, the adjacent terminal edges of said night portions being spaced 90 degrees apart.v

3. A conveying system comprising an upwardly extending conduit and a conveyor screw at the base of said conduit for urging material upwardly in said conduit, said conveyor screw having a double helical night portion wound to urge material normally in one direction and a double helical night wound to urge material normally in the opposite direction, said nights being formed with their adjacent nnal quarter turns in different quarter phases of revolution.

4. As a new article of manufacture, a conveyor screw having a double helical night portion wound to urge material in one direction and a double helical night portion wound to urge material in the opposite direction, said nights being formed with their adjacent nnal quarter turns in different quarter phases of revolution.

CHRIST T. HANSEN. 1.o 

